This document provides endotracheal tube designs with features that can improve the efficacy, patient safety, and efficiency of endobronchial access. For example, this document provides endotracheal tube designs with features for atraumatic passage of the tube's distal tip through the vocal folds. In addition, this document provides endotracheal tubes that have variations in strength and flexibility properties along the length of the tube in an advantageous pattern to enhance the efficacy of the endotracheal tube.